>> couric: tonight, two weeks into japan's disaster and it just keeps getting worse. the death toll passes 10,000 and now there may be a breach in one of the nuclear reactors. i'm katie couric. also tonight, the united states may be giving up command of the libya mission, but american forces will still be playing a major role in the operation. the fire that woke up the country to dangers in the workplace. and a population explosion. the colorful comeback of the monarch butterfly. captioning sponsored by cbs from cbs news world headquarters in new york, this is the "cbs evening news" with katie couric. >> couric: good evening, everyone. japan's prime minister says the nuclear crisis is far from over and the goal right now, he says, is simply to keep it from getting worse. but it did today with a possible breach of one of the reactors. it was two weeks ago that they were damaged when a magnitude nine earthquake shook northern japan and triggered a tsunami. the official death toll passed the 10,000 mark today. 17,000 people are still missing. and now the japanese governm